AAM 11.5 rebuild

[PLohr]

Does anyone else remember seeing either a thread on the forum or an article in the magazine that detailed the rebuild of an AAM 11. 5 rear end? I have searched both the recent magazines and the forum but have not found it. Thanks for any help.

 

[TCDiesel]

LSD or Open?

 

[PLohr]

Thank you for your response. I think either would be ok. I am interested in seeing the removal and installation of the pinion bearings and how the gear setup went.



If someone has rebuilt the AAM 11. 5 Trac-Rite carrier, I would be interested in seeing that also. Not sure they sell any parts for it though.

 

[TCDiesel]

1st You need access to a 3/4 impact that will crush the sleeve... 1/2 will NOT do it. . You also will need a wrench to hold the pinion yoke. . or 3-4ft Pipe wrench.

 

[PLohr]

Thanks for your help, TC.

Still I am hoping someone knows where this AAM 11. 5 axle rebuild thread/article is located.

 

[TCDiesel]

There is NO rebuild on the LSD the open is rebuild-able . . But why waste the time and $,its just much more profitable to replace. I have did several replacements and went to the Truetrac. Much better LSD. . its stays engage under most conditions and is much more durable,it does have a small howl at 30mph an under freewheel. If the windows are up you cannot hear it.

 

[outlaw1sammy]

Does anyone else remember seeing either a thread on the forum or an article in the magazine that detailed the rebuild of an AAM 11. 5 rear end? I have searched both the recent magazines and the forum but have not found it. Thanks for any help.

PLohr, did you have any luck finding the article/thread on rebuilding the AAM 11. 5 rear end? I think mine has a pinion bearing on its way out and I was looking for a little more information
Thanks

 

[Bob4x4]

1st You need access to a 3/4 impact that will crush the sleeve... 1/2 will NOT do it. . You also will need a wrench to hold the pinion yoke. . or 3-4ft Pipe wrench.

Interesting... ... ... . everybody in my shop uses 1/2 impacts... ... ... ... ... ...

 

[Bob4x4]

INSTALLATION









Install new front pinion bearing cup with Installer 8960 (1) and Handle C-4171 (2).









Install new rear pinion bearing cup with Installer 8968 (1) and Handle C-4171 (2).









Install pinion depth shim (1) on the pinion gear shaft (2).









Install rear pinion bearing (4) with Installer D-389 (1) and a press (1).









Install new collapsible spacer (1) on the pinion (2).

Lubricate pinion and bearings.









Install pinion into the housing (2) and place front pinion bearing onto the pinion shaft. Draw the pinion shaft into the front bearing with Installer 8981 (1).









Install new pinion seal with Installer 8896 (2) and Handle C-4171 (1).









Apply a light coat of teflon sealant to the pinion flange splines.

Hold pinion and lightly tap the pinion flange (2) onto the pinion, until a few threads are showing.

Install pinion flange washer and new pinion nut.

Hold pinion flange (2) with Flange Wrench 8979 (1) and tighten pinion nut until pinion end play is eliminated.









Rotate pinion several times to seat pinion bearings.

Measure Pinion Torque To Rotate (1) with an inch pound torque wrench (2). Tighten pinion nut in 6. 8 N·m (5 ft. lbs. ) increments until pinion torque to rotate is achieved.

Pinion Torque To Rotate is:



New Pinion Bearings: 1. 7 - 2. 8 N·m (15 - 25 in. lbs. )

Original Pinion Bearings: 1. 1 - 2. 2 N·m (10 - 20 in. lbs. )

Rotate pinion several times then verify pinion rotating torque again.









Position the ring gear (2) on differential case (4) and start two new ring gear bolts.

Install the rest of the new ring gear bolts and tighten them alternately to seat the ring gear.

Torque ring gear bolts to 237 N·m (175 ft. lbs. ).









If exciter ring was removed, position differential assembly on differential Plug 8965 and place exciter ring (1) on the differential case.

Install the exciter ring on the differential case evenly with a hammer and brass punch (2) . Drive the ring down until it is seated against the ring gear (2).

Install differential in housing.

Measure Total Torque To Rotate (TTTR) with an inch pound torque wrench.

Total Torque To Rotate is:



New Bearings: 3. 4 - 5. 6 N·m (30 - 50 in. lbs. )

Original Bearings: 2. 8 - 5. 1 N·m (25 - 45 in. lbs. )

NOTE: If TTTR is to high, back off adjusters evenly on both sides slightly and check TTTR again. If TTTR is to low, tighten adjusters evenly on both sides slightly and check TTTR again.



Verify ring gear backlash and gear contact pattern.

 

[PLohr]

Bob, thanks for helping out on this one. I will add a few things.



outlaw1sammy, if you don't have the factory service manual, it is probably a good idea to get it. I think Geno's sells a CD-R with the service manual for a reasonable price.



I have rebuilt GM 12 bolts, GM 10 bolts, and the Ford 8. 8. I have not done the AAM 11. 5 yet but I have been researching the job.



If the pinion bearings are real loose, you will need to replace the ring and pinion.



You will want to mark your ring gear with gear marking compound, turn the ring gear in the drive direction, then turn the ring gear in the coast direction. Take a few photos of the coast and drive side of the ring gear teeth, where the gear marking compound was applied. If the pinion bearings are sloppy, the contact pattern will not be correct. I like to know what the tooth contact pattern is to begin while keeping in mind how noisy the gears are. Also you want to know if the noise is on drive or coast. If the gears are wrecked, don't worry about this.



Miller 8992 pulls the pinion flange off the pinion gear. On other diffs I've serviced, we would tap the pinion flange with a brass hammer to remove it. Pretty sure you will need this tool.



On the AAM 11. 5, the front pinion bearing is pressed on. This bearing is not a press fit on these other differentials that I mentioned. Miller part number 8977 is intended to remove the pinion gear from the bearing while still in the housing. It's possible a large brass punch will do the trick but if the pinion gear is very tightly pressed into the bearing, you will want the 8977 tool.



You will need a long steel punch to drive out the pinion bearing races. Careful not to damage the cast iron housing. If you have a brass punch long enough for the task, use it instead. Usually the brass punches are not long enough.



A set of race and seal drivers will be needed to install the new pinion races. The factory service manual shows six different pieces for installing races and seals. You might purchase the pinion bearings, races, and seal first then figure out what size drivers you need. The seals and races may be so large that a typical race and seal driver kit from Snap-On or Mac may not suffice.



A bearing splitter will be needed for the rear pinion bearing and for the carrier side bearings. Use the splitter with a hydraulic press or get a bridge (Miller 938 or equivalent). I never tried a bridge... was lucky enough to have a press.



You can run a ball hone through the rear pinion bearing's press fit surface since it will need to go on and off a few times. Not too much though... it still needs to be a press fit. Clean the rear pinion bearing well after honing it.



Setup the gears without the crush collar in to establish the tooth contact pattern. Put the OEM pinion shim in with your new gears to start. With your installation kit you should have a handful of pinion shims. The instructions that came with your new gears will tell you to change the pinion shim to move the tooth contact pattern in or out. You may have to change the shim a few times which means disassembling and reassembling a few times. Backlash is adjusted with the Miller 8883 wrench.



Miller 8979 is used to hold the pinion flange while tightening the pinion assembly against the crush collar. You might be able to build something instead but it could be less trouble to just get the Miller 8979. You will also need a 3/4" or 1" drive very long (3 to 4 feet) ratchet or breaker bar with the corresponding impact socket to tighten the pinion nut. Northern tool should have these items. This setup will always get the job done. A big impact gun may work... it is a gamble. The crush collar is put in after we have our tooth contact pattern looking good. Probably want to have 2-3 crush collars sitting around just in case.



I always checked the pinion bearing preload as I turned the pinion by hand. Factory service manuals always say to use a small (3/8" drive) dial gauge torque wrench. This is probably a good idea unless you know what the preload should feel like.



I would ask a few of the companies that manufacture gears about the tooth contact pattern since there is conflicting information. Maybe finding instruction sheets online will give you this information. Chrysler likes it dead center on the coast and drive (factory service manual). Aftermarket gear manufacturers will tell you to setup the gears so the drive side is at the root of the tooth and the coast side is closer to the center of the tooth. Richmond, Zoom, and Ford Motorsport gears all liked it this way. I had always done it this way. OEMs are known for noisy ring/pinion setups and this may be why. We ended up with very good results following the aftermarket instructions on gear setup.



A dial gauge indicator and dial gauge will be needed to measure backlash.

 

[outlaw1sammy]

Thanks for sharing your knowledge guys